Instagram said it does not comment on third party studies, so could not confirm whether the figures are accurate.

It added that it takes transparency seriously and marks adverts that appear on Instagram as "sponsored".

"Understanding where sponsorships or endorsement deals do or don't exist is a complex challenge for the industry - online and off - and we are exploring what works best for our community. We encourage everyone in the Instagram community to follow local industry guidelines around transparency with any sponsored content," the statement said.

Last month Instagram revealed it is trialling a new tool to bring transparency to branded content on the platform, through a new "paid partnership with" tag on posts and stories.

"The tool allows a creator to tag business partner they are working with and provides access to insights for the content created as part of this partnership. We are initially working with a few launch partners with the goal to learn and gather feedback. This is a first step and we hope to roll it out globally to brands and creators in the coming months," it said.

"In the last couple of years influencers and celebrities have really caught on to the fact that endorsing brands on Instagram pays off and as you can see from our rich lists, there is a serious amount of money to be made," he said.

"However, it is important that Instagram users are aware their favourite celebs and bloggers are being paid to promote products and services so they can understand when they are being sold to as part of content. The recent introduction of the 'paid partnership' label will go some way to ensuring there's more transparency on the platform."